The present invention relates to a container treatment device for expanding pre-forms into containers, having at least one blow moulding device for introducing a flowable medium under pressure into an inner space of the pre-form, and at least one stretching device for stretching the pre-form during an expansion procedure.
The container treatment device according to the invention, which also has a stretching device in addition to a blow moulding device, is consequently preferably a stretch/blow moulding device for stretch blow moulding or expanding respectively a pre-form and, in particular, a plastics material pre-form, into a container and, in particular, a plastics material container, such as for example a beverage bottle.
A stretch/blow moulding device with a stretching device and a blow moulding device is known for example from WO2008098565, this stretch/blow moulding device having a plurality of components or elements respectively, such as for example inter alia a threaded rod and a stretch rod carrier connected to it by way of a coupling element for moving the stretch rod into a pre-form to be expanded or out of an expanded container respectively, or a coupling arranged between a shaft of a motor and the threaded rod, in order to ensure not only a blow moulding process but, in addition, also a stretching process for expanding a pre-form. It is clearly evident from the stretch/blow moulding device of WO2008098565 that an independent or additional linear guide of the stretch rod is always necessary, in which case covering elements have to be additionally introduced in order to prevent contamination of the stretch rod by the threaded rod for example. In addition, the complex design of the stretch/blow moulding device of WO2008098565 prevents the stretch rod from being able to be replaced in a simple and rapid and therefore inexpensive manner in case of need. In fact, the stretch rod is arranged between individual devices, such as for example the pneumatic valve or the stretch rod carrier respectively and the pneumatic block, in such a way that a time consuming dismantling of a plurality of structural elements is necessary in order to make a replacement of the stretch rod possible.
A comparable complex design of a stretch/blow moulding device is also displayed for example by EP 0 577 384 A1, which discloses an arrangement of a stretch rod over a carrier guided in a linear manner, this carrier in turn being operatively connected to a threaded rod coupled to a motor shaft, in such a way that the carrier is moved up and down in a translational manner by the rotational movement of the threaded rod. In this case too there is again a need for an additional linear guidance of the stretch rod, namely the carrier interacting with the threaded rod, as a result of which the stretch/blow moulding device of EP 0 577 384 A1 not only is also costly and maintenance intensive, but also does not allow a rapid and simple change of the stretch rod.
Accordingly, the object of the present invention is to make available a container treatment device, and in particular, a stretch/blow moulding device for expanding pre-forms into containers, which, in particular with respect to the devices named above, has a form designed in a structurally simple manner and with a small number of structural elements, in order to reduce the production costs, assembly costs and maintenance costs of the device, and in which the device itself is to be designed in such a way that a simple replacement of the stretch rod is made possible, and in which, in particular, the occurrence of components which contaminate the stretch rod is to be reduced, in order to prevent contamination, such as oil, grease and so on, which is capable of reaching the stretch rod and thus the container which is to be expanded.